1. Field of the Invention
This invention relates to a hydrous gel of a novel structural form comprising a continuous phase composed of a certain elastomer and an oil component and an emulsified water phase, and a process for its preparation, and more specifically, is characterized in that as a result of the presence of the emulsified water phase in the form of a w/o emulsion in the gel structure, the hydrous gel has unique physical, mechanical and chemical properties as compared with conventional aqueous gels or oily gels.
2. Description of the Prior Art
Relatively sort aqueous gels comprising various water soluble organic polymeric compounds, such as starch, cellulose derivatives, gelatin, casein, polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylic acid, or polyethylene oxide, are known, and find applications as fire-retarding materials and insulating (heat and cold retention) materials, etc. Most of these aqueous gels, however, are of such a form that they are swollen as a result of the absorption of water by the water soluble polymers. Hence, in most of these aqueous gels water forms a continuous phase. For this reason, when the water content is relatively high, the strength of the aqueous gel is not so high, and generally, it has poor storage stability. When such aqueous gels are allowed to stand in the air, water present therein evaporates off easily. Furthermore, when such aqueous gels are utilized as a cold-retaining material and are stored at a temperature below 0.degree. C., they suffer from the defect that the entire gel freezes and becomes very hard and brittle, thus losing its softness.
Japanese Patent Publication 18,409/72 discloses the preparation of a highly elastic gel composed of an elastomeric block copolymer and a certain oil or a higher fatty acid as an oily gel which, in particular, has good softness and high elasticity. The oily gel disclosed, however, has a rubber like high impact resilience and easily deforms upon the application of stress but returns to its original state upon removal of the stress. Accordingly, it has very poor stress dispersing characteristics as will later be described. Furthermore, since this oily gel is combustible, it is unsuitable for use as a fireproofing material, and because it does not contain a water phase, it has practically no insulating (cold retention) effect.